CHAPTER IX 



SYSTEMATIC ARRANGEMENT OF THE FORAMINIFERA 



In the following pages the families, subfamilies and genera 

 are taken up in systematic order. Descriptions are short and 

 simple, as to give fully all the details of the genera would make 

 this work more than a single volume. Figures are given of 

 practically all the genera treated here. The type figure is often 

 copied, or where it is not adequate for the full understanding of 

 the genus a later figure of the species is usually given. Other 

 species are given in many genera for comparison, and many 

 more figures could have been used to advantage but there are 

 limits to the illustrations that can be used. A very careful 

 selection of figures has been made to have those which would 

 give the clearest idea of the necessary structural points. Sec- 

 tions are used throughout for a fuller understanding of the 

 structure. 



A few of the plates show the relationships of the genera in 

 the families and the lines of development. The other plates give 

 various views of typical specimens. A key is given to the fam- 

 ilies but it is not complete in its details. Many of the genera in 

 various families assume so many forms that it is difficult to get 

 the full details into a simple statement of a line or so. As the 

 student will gain much more from working with actual speci- 

 mens than with the best of books, he will soon learn in which 

 families various forms belong. In those families where there 

 are numerous genera, simple keys are given. The student should 

 not depend upon them except as aids, and then should carefully 

 check the fuller generic characters in the text. 



The genotypes are given under each genus. Wherever the 

 genus in monotypic, and whether the actual genoholotype 

 species was designated as such or not, the type species has been 

 here called a genoholotype. Designation of genotypes has been 

 made if other authors have not already done so in genera where 



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